Ice-liquid separation column

ABSTRACT

Mechanism for separating a concentrated solution of soluble solids from a solvent previously frozen into crystals thereof, providing means in which a column of the crystals is arranged into a loosely packed mass highly capable of rising by natural buoyancy in the solution in the column while holding smaller crystals in the rising mass and permitting the concentrated solution to drain from the upper portion of said rising column and thereby separate the same from said frozen crystals, applying a washing spray of the same solvent to the top of said rising column, and continuously removing the washed crystals from the top of said column of crystals to permit the column to continue to rise while draining concentrated solution therefrom.

United States Patent {72] Inventor [54] ICE-LIQUID SEPARATION COLUMN 6Claims, 7 Drawing-Figs.

[52] U.S.Cl 62/123 [51] lBllldQ/M [50] Field of Search 62/123, 124, 5 8

H'IHIIIHII {56] References Cited UNITED STATES PATENTS 3,251,193 5/1966Wiegandt 62/123 X Primary Examiner-William E. Wayner Att0rneyC. HercusJust ABSTRACT: Mechanism for separating a concentrated solution ofsoluble solids from a solvent previously frozen into crystals thereof,providing means in which a column of the crystals is arranged into aloosely packed mass highly capable of rising by natural buoyancy in thesolution in the column while holding smaller crystals in the rising massand permitting the concentrated solution to drain from the upper portionof said rising column and thereby separate the same from said frozencrystals, applying a washing spray of the same solvent to the top ofsaid rising column, and continuously removing the washed crystals fromthe top of said column of crystals to permit the column to continue torise while draining concentrated solution therefrom.

PATENIEI] man an 3 6 2 8 3 4 sum 1 OF g INVENTOR ALFRED T- KING BY Z MawATTORNEY PATENTED BEBE! ml SHEET 2 UF 2 INVENTOR ALFRED T. KING M 1, BY7 Java"; Zk-/ ATTORNEY ICE-LIQUID SEPARATION COLUMN This application isa continuation-in-part of applicant's prior application, Ser. No.799,653, filed Feb. 17, 1969 and abandoned upon the filing of theinstant application.

CROSS-REFERENCE TO RELATED APPLICATION The present invention is a unitwhich may be employed in the system comprising the subject matter ofcopending application, Ser. No. 799,714, filed Feb. 17, 1969.

BACKGROUND OF THE INVENTION The separation of certain types of dissolvedsolutes in liquid solvents by subjecting the same to freezing so as tofreeze the liquid solvent, where possible, to effect separation from thedissolved solute is a phenomenon which has been used in a number ofdifferent fields of activity, such as the separation of potable waterfrom sea water. Another field is that of beverages, wherein solutions ofcoffee, tea, fruit juices and the like, have been subjected to freezingin order to concentrate the solute or beverage extract and therebypermit the same to be separated from as much of the liquid solvent aspossible, which normally is water, following which the concentratedsolute is dried so as to form a dry, powdered type of beverage extractwhich can be reconstituted merely by the addition of water, either hotor cold.

in regard to the so-called desalination of sea water, the normal desiredproduct is the potable water, whereas the concen trated solute orextract normally is discarded, although it is conceivable that it couldbe dried to form certain types of unrefined salt complexes. However, thedesired product under such circumstances is exactly opposite that whichis normally desired in using the so-called freeze-type technique,referred to above, with respect to producing dried or powdered-typebeverage concentrates or extracts. Thus, in said desalination of seawater, the manner and method of treating the removed concentrated saltextract is of little concern since it is the water which is separatedfrom such concentrate that is the desired product.

In regard to using such freezing technique to produce a concentratedbeverage extract, and particularly when producing coffee extract so asto provide a natural type of delicate aroma and flavor characteristic offresh brewed coffee, it is highly important that certain precautions beexercised in the treatment of the concentrated solute comprising thebeverage extract incident to freezing the water solvent and separatingthe same from the extract. One of the processes presently used toseparate such concentrated beverage extract from the ice crystalscomprising the frozen water solvent includes the use of special typesofcentrifuges.

During the operation ofsuch centrifuges, it is found that the liquidconcentrate is very extensively broken up, as well as being aerated. ltalso is caused to foam. The foam is difficult to control and theaeration resulting therefrom causes subsequent oxidation which resultsin a greatly degraded product due to poor flavor. Also, centrifuges ofthe type now used constitute a substantial capital investment andrequire the use of a motor of considerable power, as well as alsorequiring continual maintenance.

Typical examples of several types of desalination apparatus which havebeen devised heretofore are illustrated in U.S. Pat. No. 3,25l,l93, toWiegandt, dated May l7, 1966, and U.S. Pat. No. 3,333,436, to Johnson etal., dated Aug. 1, 1967. Examples of previously developed devices forforming concentrated beverages and fruit juices are illustrated in U.S.Pat. No. Re 23,810 to Schmidt, dated Mar. 30,1954, and U.S. Pat. No.3,342,039, to Bridge et al., dated Sept. 19, 1967.

SUMMARY OF THE lNVENTlON It is the particular object of this inventionto provide a method and apparatus that can be employed in a freezeconcentration process for removing water, as an example of a solvent, inthe form of frozen ice crystals, from a water-bearing beverage substancesuch as coffee, tea, fruit juice, vegetable juice, milk, beer, wine,pharmaceuticals and other heat sensitive solutions or suspensions.

it is also an object of this invention to provide a means for separatingfrozen ice crystals from a solution or suspension which entrains thesame and uniformly and gently washes the crystals to efficiently removethe desired concentrate therefrom, thereby producing a substantiallycomplete separation of highly concentrated solution of the desiredsolute from the crystals of solvent, after which, if desired, the solutemay be further concentrated and/or dried.

It is also an object of this invention to provide an apparatus forseparating frozen ice crystals from a solution or suspension by meanswhich cause no aerating of the solution or suspension.

It also is an object of this invention to provide a means for separatingfrozen ice crystals from a solution or suspension of beverageconcentrate that will operate continuously and require very little or noattention.

it is also an object of this invention to provide a simple apparatusthat consumes very little power, requires very little maintenance andwill serve as a highly suitable substitute for the customary centrifugein conventional freeze concentration processes for separating aconcentrated solution of solute from frozen crystals of a solvent.

It is also an object of this invention to provide a means for protectinga solution from atmospheric air as frozen crystals are being separatedfrom the solution.

It is also an object of this invention to provide means for enclosingthe region in which a solution or suspension is separated from frozencrystals, whereby said region can be saturated with an inert gas toavoid contact of the solution or suspension with air and thereby reducesubsequent oxidation.

it is a further object of this invention to provide an aparatus andmeans whereby the buoyancy, or natural tendency of frozen ice crystalsto float, is employed to cause the crystals to rise above the liquidlevel gently and without agitation and while the ice crystals are atleast in moderately loose condition, whereby the crystals can becontinuously washed efficiently and removed without disturbing thecontinuously rising column of frozen crystals.

It is still another object of this invention to provide apparatus andmeans to accept a continuous uniform flow of a solution of a beverageextract, such as coffee, for example, that has been at least partiallyfrozen and contains ice crystals comprising frozen solvent, admit saidmixture of extract and ice crystals to a vertical hollow cylinder orcolumn of uniform interior diameter which is approximately twice thediameter of the inlet pipe that is connected to the lower end of thecolumn and through which said mixture enters the column, whereby thecolumn is large enough in diameter to reduce the velocity of the columnof extract and ice crystals and permit it to rise gently in the hollowcylinder, while the crystals tend to loosen and separate from thecompact nature in which they are delivered to the bottom of thecylinder. The upwardly moving mixture of concentrated beverage extractand ice crystals rises to a relatively high level where the extractdrains by gravity away from the rising but undisturbed column of icecrystals, preferably through vertical slots provided in closely spacedmanner in the circumference of the hollow cylinder. Said slots are highenough in the cylinder to provide clear space within the hollow cylinderfor the ice crystals to collect therein and form a loosely packed columnof the same, which floats by natural buoyancy within the fluid extract,due to there being sufficient body below the extract liquid level toprovide the buoyancy necessary to cause the top of the ice crystalcolumn to rise sufficiently above the liquid level that it is accessibleto be gently sprayed uniformly with a controlled wash of the liquidsolvent which drains into the liquid concentrate while the clear icecrystals at the top of the column continually are removed by a suitablescraper.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of anexemplary device embodying the invention which has the cover partiallybroken away to reveal details therein.

FIG. 2 is a right side elevation of the device shown in FIG. 1.

FIG. 3 isa plan 'view of the device shown in FIGS. 2 and 3.

FIG. 4 is a diagrammatic view of exemplary water spray piping for thedevice.

FIG. 5 is a fragmentary enlarged top plan view of the device shown inFIGS. 1-3 with the enclosing shell removed therefrom.

FIG. 6 is a fragmentary enlarged side elevation of part of the deviceshown in FIG. 5.

FIG. 7 is a still further enlarged vertical elevation of the deviceshown in FIGS. 5 and 6, parts thereof being in vertical section.

Referring to the drawings, the infeed pipe 1 for the mixture ofconcentrated extract and ice crystals communicates with freezingapparatus of suitable type, such as that of the subject matter of Ser.No. 799,714. The crystals are, for example, from 0.004 to 0.010 inchesin size. In processes of this type, these are regarded as relativelylarge. Elbow 2 and reducer 3 connect the infeed to vertical hollowcolumn or cylinder 4, which is of uniform diameter and'preferably abouttwice the diameter of pipe I.

This arrangement permits the ice crystals to expand and separate orloosen up from the somewhat compact condition thereof in which they aredischarged from pipe 1. Thus, the liquid concentrate separates from thecrystals more readily and the buoyancy of the crystals in the liquid isenhanced. The mixture rises by such buoyancy in the cylinder until itreaches the discharge means at the top of the cylinder.

The discharge means comprises a closely spaced series of very narrow orfine vertical slots 5 which extend circumfcrentially around the upperportion of cylinder 4. The width of said slots is less than the diameterof the majority of the ice crystals in the mixture rising within thecylinder 4. While the mixture of liquid beverage concentrate and icecrystals of water solvent is so rising, theconcentrate is completelyenclosed from outside air and is not agitated to any appreciable extent,nor is it caused to froth or foam, thus minimizing oxidation of theconcentrate. Hence, flavor and aroma characteristics are maintained at avery high level, which is far greater than in the product resulting fromconventional centrifuging operations.

The height of the cylinder 4 is sufficient that very substantialbuoyancy is afforded the ice crystals so as to cause the uppermostportion of the column thereof to rise above the level of the liquidconcentrate in the column and thus enhance drainage of the concentratetherefrom to facilitate recovery of the concentrate by separation fromsuch crystals. While such rising of the mixture is occurring, the upperlevel of the concentrate reaches the slots 5 and gently and graduallydrains therefrom.

Desired gradual and gentle drainage of the liquid concentrate also isenhanced by the use of the vertical slots 5 as distinguished from aseries of holes, for example, if used for discharge of the liquid.

When the crystals move upwardly along said slots, the edges of the slotsactually act somewhat as guide tracks along which the crystals slidewithout agitation or impedance. If holes are used, there obviodsly is atendency for individual crystals to become lodged therein and thusimpede movement of the crystals, as well as prevent draining of liquidtherethrough. There also is a tendency toward jostling and agitation bythe crystals bumping past the holes. The benefit of the slots also isfurther increased by the fact that the slots extend to within about aninch of the top of the cylinder so that an appreciable extent ofdraining of liquid from the crystals occurs while the latter moveupwardly for removal at the top of the cylinder, in drained condition.

Without limitation thereto and solely for purposes of illustration, itis submitted that a practical example of a deviceof the type hereindescribed has been used successfully in which the cylinder 4 isapproximately 4% inches in interior diameter and not less than about 2%feet long from the lower end to the upper end, including the upperslotted portion. The diameter of inlet pipe 1 and elbow 2 is 2% inches,the radius of elbow 2 is approximately 3 inches, and the slots 5 areapproximately 5% inches long, which has been found to provide adequatedrainage of the liquid concentrate in a nonagitated manner. All of theelements engaged by the liquid concentrated solute were made of 304stainless steel.

Just below the lower extremity of the slots 5, a suitable catch pan 6 isfixed in liquid tight relation to the vertical cylinder, such as bywelding. Pan 6 may be made of sheet metal, such as stainless steel andhas a sloping bottom 7 to conduct the discharge of extract to andthrough discharge pipe 8 which is the outlet for the concentratedextract. Inlet pipe 1, elbow 2, reducer 3, vertical column 4, catch pan6, sloping bottom 7, and outlet pipe 8 preferably are welded into oneunitary structure which is free of leaks. This assembly is enclosed in asuitable thickness of thermal insulation within jacket 9 which extendsfrom the underside of the catch pan 6 to near the inlet end, asillustrated.

A suitable frame having legs 36 supports the abovedescribed assembly. Acover or jacket 37 also is provided to completely enclose the insulatedpipe and support frame assembly, thereby protecting the concentratedextract from contamination and exposure to atmospheric air as it flowsinto catch pan 6 so as to further prevent oxidation of the concentrateand thus protect it. If desired, the space under cover 37 can be floodedor maintained in saturated condition with an inert gas, from a suitablesource represented by pipe 38, to insure that the concentrated extractdoes not contact air to oxidize the same.

A circular receptacle or pan 10 having a tangential discharge chute 11is fixed to the top of column 4 which passes through the bottom of pan10 as clearly shown in FIG. 7. The bottom of circular pan 10 preferablyis level with and is fixed to the top-of vertical column 4 and the panalso has sides that enclose but are clear of the ends of the ice scraper12. The ice scraper 12 is concentric with circular pan l0 and circularpan l0 and scraper 12 are both eccentric relative to the top of verticalpipe 4. As the ice scraper 12 rotates, each blade of the scraper willpass transversely across cylinder 4, as shown by arrow 13, and icecrystals will be scraped or shaved off of the top of the ice crystalcolumn and fall into the tangential chute 11 which preferably extendsdownwardly, as shown in FIG. 1.

By such an arrangement, an actual transverse shearing of the column ofice crystals occurs and positive separation and discharge thereof intochute 11 is effected. As seen from FIG. 5, the blade 12 will not onlyshear the projected ice crystals from the column, but will alsopositively push them axially into the chute 11. Hence, this arrangementis much more effective than a scraper which, for example, rotatescoaxially with cylinder 5, under which circumstances, the rotating bladeprimarily would merely rotate the column of ice crystals about the axisof cylinder 5.

The vertical drive shaft 14, on which ice scraper 12 is mounted, isdirectly connected to a motor and reducer unit 32 which turns icescraper 12, by way of example and not limitation, approximately 30revolutions per minute in the direction of arrow 13. Vertical shaft 15is mounted in bearing block 18 so as to be parallel to drive shaft 14and coaxial with vertical cylinder. Vertical drive shaft 14 drivesvertical shaft 15 by means of one or more small V-belt pulleys 16 andV-belts 17.

Vertical shaft 15 rotates in bearings 20 and 21 formed ofself-lubricating material such as nylon synthetic resin and supported inblock 18. A controlled water supply is connected to tapped hole 19 whichcommunicates with annular manifold groove 22. Water is conducted fromthe annular groove 22, by radial hole 23 and vertical hole 24,'to spraynozzle 26 which is carried by the lower end of shaft 15. O-rings 25retain the water and prevent leakage as the vertical shaft 15 rotates.

The inlet pipe 27 is connected at its outer end to a suitable source ofwater supplied 'at uniform pressure and controlled uniform' temperature.Needle valve 28 controls the flow of water to nozzle 26 and pressuregauge 29 indicates the pressure in pounds per square inch imposed uponnozzle 26. Temperature gauge 30 indicates the temperature of water beingsprayed on the column of ice crystals.

Nozzle 26 may be adjusted to control the amount of water used and thecharacter of the spray. For simplification, two nozzles were selectedand a table was compiled giving the gallons per minute passed by eitherof the two nozzles at different pressures as indicated by pressure gauge29. For convenience of the operator, a table 31 is shown in FIG. 1 asbeing permanently affixed conveniently to housing and sets forth thenozzle delivery rates from 0.05 to 0.21 gallons per minute at differentpressures as shown on gauge 29.

Noule 26 emits a flat fanshaped spray 32' no wider than the diameter ofcolumn 5, as shown in FIG. 7, and the rotation assures a uniformdistribution of wash water constantly across the entire upper surface ofthe ice column as it rises. The spray pattern may be varied byvertically adjusting block 18. The rate of spray discharged from nozzle26 is regulated relative to the rate of feed of the mixture of liquidconcentrate and ice crystals to the bottom of cylinder 1 so as toprovide a suitable amount of washing of the crystals without unduedilution of the concentrate.

The protective housing 34 which extends over the motor reducer 32provides a convenient panel 35 upon which is mounted motor controlswitch 33, needle valve 2%, pressure gauge 29, thermometer 30 and table31.

In performing the process herein described, the mechanism is activatedand after a relatively short run at a certain selected speed, thecrystals discharged and the specific gravity of the liquid concentrateare inspected and determined. if found to be satisfactory, the operationis continued. If not satisfactory, various things may be and areadjusted, such as, for example, the freezing rate and degree oftemperature produced by the freezing equipment, not shown, whichproduces the crystals fed to the inlet pipe 1, and the rate of feed ofthe mixture of crystals and liquid concentrate, until desired productsare produced.

Reference is made hereinabove to the frozen crystals being of anexemplary size range between 0.004 and 0.010 inches in diameter. Thisrange, under some circumstances, may be as large as 0.025 or even 0.030inches in diameter. Crystals of these size ranges, especially incomparison with the sizes of the seed crystals from which they areformed, are considered to be relatively large crystals. Such crystalsprovide ready and effective separation of the frozen solvent, which theycomprise, from the solute or concentrated extract during the rising ofthe column ofcrystals within column 4.

To further clarify the application of this invention, the followingexample is set forth:

EXAMPLE A flow of coffee extract from a freeze concentration system isfed directly to inlet pipe 1 at a uniform rate. This coffee extract hasbeen previously exposed to freezing conditions to develop crystals ofpure ice intermixed with the liquid cofiee extract. As the mixture flowsinto the enlarged vertical column 4, the velocity is markedly reduced.The mixture gradually rises toward the upper end of vertical column aand the liquid extract drains away from the crystals through slots 5,leaving the ice crystals in a relatively loosely packed floating masswhich is constantly buoyed upwardly. The length of this column below theliquid level provides the buoyancy that causes the column to rise to theupper end of the vertical column 4, where it is sprayed with water 32'and scrapers 12 progressively remove the ice. The spray of water 32'washes the ice and flows down through it. Some of this water passes offwith the ice as it is scraped off and the remainder flows down throughthe ice and mixes with the concentrated extract. A regulation of theamount of water sprayed controls the purity of the ice and the surplusthat enters the concentrated extract.

Assuming that the above is a first stage of freeze concentration, thefollowing would be a typical operation:

EXTRACT FEED 1201.1 1 pounds of liquid per hour at 1.098 specificgravity or 22.5 percent soluble solids 1201.1 1X0.225=270.24975 lb. perhour solids CONCENTRATED EXTRACT 1.138 specific gravity or 31 percentsoluble solids 270.25

0.3l=871.77,419 lb. per hour concentrated liquid extract 1201.1 1 lb.per hour liquid feed at 22.5 percent solids 871.77419 lb. per hourliquid concentrate at 30 percent solids 329.33581 lb. per hour iceremoved ln the above operation, the water spray would be diluting theconcentration of the extract. The water spray would be set to deliverapproximately 0.12 gallon per minute or,

0. 1 2 8.336 60=60 lb. ofspray per hour One-half of this amount, 30 lb.per hour, or less would dilute the concentrate as follows:

871.77 lb. per hour 30. lb. per hour 841.77 lb. per hour Therefore, thespray has diluted the concentration from 32 percent to 31 percent.

The above conditions would be varied for different materials and to meetvarious requirements. A second stage of a recycling operation undertakenmay be added to arrive at higher concentrations of the solute.

As referred to hereinabove, the nozzle 28 is shaped and designed to emita flat fan-shaped spray 32. Also the width of said spray and the heightof the same above the column are so arranged that, as viewed in FIG. 7,the widest portion of the spray is no greater than the diameter of thecylinder 5 within which the column of a mixture of liquid concentrateand ice crystals is rising. Accordingly, there is maximum effective useof the spray water, due especially to the fact that the nozzle isconstantly rotating at the exemplary speed referred to hereinabove,whereby the entire area of the upper end of the rising column of icecrystals is contacted by the spray water in a highly efficient mannerwhich insures washing of the entire body of the upper portion of therising column of crystals, with a minimum of excess dilution of theliquid concentrate. As a result, at the expense of a limited amount ofdilution of the concentrate, separation of substantially the entireamount of liquid concentrate from the ice crystals is assured and thus,no appreciable amount of the concentrate is lost when the ice crystalsare separated from the upper end of the column for discharge to chute1.11.

Also, due to the fact that the washing spray is introduced at the verytop of the column of rising ice crystals from which nearly all of theconcentrate has naturally drained by gravity or washed therefrom and hasbeen discharged through the slots 5 at the upper end of cylinder 1, thepossibility of introducing ambient air into the liquid concentrate bythe spray water is negligible, thereby further minimizing thepossibility of oxidizing the liquid concentrate which would impair theflavor and aroma thereof.

From the foregoing, it will be seen that the apparatus comprising thesubject matter of the present invention is relatively simple and sturdy,requires minimum servicing and attention, and is highly efficient toseparate substantially all liquid concentrate of a beverage extract fromthe frozen solvent which is in the form of ice crystals which arecontinuously removed from the upper end of the column of rising mixture.The rising column of ice crystals also is effectively washed to insuremaximum recovery of the liquid concentrate without wasting the samein'the discharged ice crystals.

The handling and treatment of the liquid concentrate during the entire,procedure also is such as to provide gradual and gentle movement thereofwhile out of contact with the ambient atmosphere and without agitatingor causing frothing of the liquid concentrate in any way, whereby thequality of flavor and aroma of the liquid concentrate is maintained at avery high level and closely approaches that of freshly brewed beverage,especially when the liquid concentrate being recovered comprises brewedcoffee or tea.

While the invention has been described and illustrated in its severalpreferred embodiments, it should be understood that the invention is notto be limited to the precise details herein illustrated and describedsince the same may be carried out in other ways falling within the scopeof the invention as illustrated and described.

lclaim:

1. Apparatus operable to separate a liquid beverage concentrate solutefrom a mixture with frozen crystals of solvent, said apparatuscomprising in combination, a vertical cylinder of substantially uniformdiameter having a solution inlet conduit of smaller diametercommunicating with the lower end thereof to permit loosening of thecrystals in said rising column thereof and said cylinder also being freeof obstructions therein, thermal insulation surrounding said inlet andcylinder, discharge means for the liquid concentrate solute directly inthe walls of the cylinder adjacent the upper end thereof comprisingparallel narrow vertical slots of a width adequate to pass substantiallyonly concentrated liquid solute and prevent the passage of frozencrystals of the size entrained in said concentrated liquid solute, a pansurrounding and fixed to said cylinder immediately below the lower endsof said discharge slots and shaped to receive concentrated liquid solutedischarged by gravity thereto from said slots and having discharge meansto conduct said solute from said pan, said cylinder being sufficientlylone to support a column of frozen crystals by natural buoyancy withinand by the concentrated liquid solute within said cylinder and adaptedto float the upper end of said column of crystals to a level projectingabove the upper end of said cylinder to permit substantially completedraining of the solute therefrom by gravity, and

crystal removal means mounted for movement transversely to the axis ofsaid cylinder adjacent the upper end thereof and operable to shearinglyseparate from said rising column of crystals the uppermost portionthereof which projects above the upper end of said cylinder to therebyremove the same from said apparatus and concentrated liquid solute.

2. The apparatus according to claim 1 in which said crystal removingmeans comprises a blade rotatable about an axis parallel to saidcylinder and adjacent one side thereof to effect movement of said bladein an arc transversely across the top of said cylinder in a manner toshave from the column of crystals therein the uppermost portion thereofprojecting above the upper end of said cylinder.

3. The apparatus according to claim 2 further including a panlikereceptacle surrounding the upper end of said cylinder and connectedthereto, said pan having a rim within which said blade operates and atangential discharge chute which slopes downwardly and is operable toreceive crystals shaved from the column thereof by said blade.

4. The apparatus according to claim 1 further including a liquid spraynozzle dependingly supported vertically above the upper end of saidcolumn of ice crystals and operable to spray a pattern of liquid washingsolvent no wider than the upper end of said cylinder directly upon therising column of crystals and thereby wash the same relatively free fromadhering concentrated solute.

5. The apparatus according to claim 4 in which said nozzle is shaped todischarge a relatively flat fan-shaped jet of washing liquid of whichthe widest dimension is no greater than the diameter of said cylinderand said nozzle being supported for rotation about the vertical axis ofsaid cylinder, and means to rotate said nozzle at a relativelyslowspeed.

6. The apparatus according to claim 4 in which said nozzle is shaped todischarge a diverging spray spreading downward and outward from saidnozzle, and said apparatus further including means to adjust said nozzlevertically toward and from the top of said column of ice crystals tovary the width of said spray at its engagement with said top of saidcolumn of ice crystals.

1. Apparatus operable to separate a liquid beverage concentrate solutefrom a mixture with frozen crystals of solvent, said apparatuscomprising in combination, a vertical cylinder of substantially uniformdiameter having a solution inlet conduit of smaller diametercommunicating with the lower end thereof to permit loosening of thecrystals in said rising column thereof and said cylinder also being freeof obstructions therein, thermal insulation surrounding said inlet andcylinder, discharge means for the liquid concentrate solute directly inthe walls of the cylinder adjacent the upper end thereof comprisingparallel narrow vertical slots of a width adequate to pass substantiallyonly concentrated liquid solute and prevent the passage of frozencrystals of the size entrained in said concentrated liquid solute, a pansurrounding and fixed to said cylinder immediately below the lower endsof said discharge slots and shaped to receive concentrated liquid solutedischarged by gravity thereto from said slots and having discharge meansto conduct said solute from said pan, said cylinder being sufficientlylone to support a column of frozen crystals by natural buoyancy withinand by the concentrated liquid solute within said cylinder and adaptedto float the upper end of said column of crystals to a level projectingabove the uppEr end of said cylinder to permit substantially completedraining of the solute therefrom by gravity, and crystal removal meansmounted for movement transversely to the axis of said cylinder adjacentthe upper end thereof and operable to shearingly separate from saidrising column of crystals the uppermost portion thereof which projectsabove the upper end of said cylinder to thereby remove the same fromsaid apparatus and concentrated liquid solute.
 2. The apparatusaccording to claim 1 in which said crystal removing means comprises ablade rotatable about an axis parallel to said cylinder and adjacent oneside thereof to effect movement of said blade in an arc transverselyacross the top of said cylinder in a manner to shave from the column ofcrystals therein the uppermost portion thereof projecting above theupper end of said cylinder.
 3. The apparatus according to claim 2further including a panlike receptacle surrounding the upper end of saidcylinder and connected thereto, said pan having a rim within which saidblade operates and a tangential discharge chute which slopes downwardlyand is operable to receive crystals shaved from the column thereof bysaid blade.
 4. The apparatus according to claim 1 further including aliquid spray nozzle dependingly supported vertically above the upper endof said column of ice crystals and operable to spray a pattern of liquidwashing solvent no wider than the upper end of said cylinder directlyupon the rising column of crystals and thereby wash the same relativelyfree from adhering concentrated solute.
 5. The apparatus according toclaim 4 in which said nozzle is shaped to discharge a relatively flatfan-shaped jet of washing liquid of which the widest dimension is nogreater than the diameter of said cylinder and said nozzle beingsupported for rotation about the vertical axis of said cylinder, andmeans to rotate said nozzle at a relatively slow speed.
 6. The apparatusaccording to claim 4 in which said nozzle is shaped to discharge adiverging spray spreading downward and outward from said nozzle, andsaid apparatus further including means to adjust said nozzle verticallytoward and from the top of said column of ice crystals to vary the widthof said spray at its engagement with said top of said column of icecrystals.